Mg-Y合金的中高温力学行为

Mechanical Behavior of Mg-Y Alloys at Medium-to-High Temperatures

随着现代工业对轻量化结构材料的需求不断增长,具备高比强度、低密度特性的镁(Mg)合金受到了广泛的关注。将特殊元素作为主要合金元素,可极大提高镁合金的抗蠕变性能和热稳定性,特别是钇(Y)元素,不仅价格较低,而且形成Mg-Y合金后,兼具较高的固溶强化效果和优良的热稳定性,未来极具应用潜力。从Mg-Y合金的热变形行为着手,梳理了Y元素含量对Mg-Y合金蠕变行为与抗蠕变性能的影响,探讨了改善Mg-Y合金抗蠕变性能的方法,形成了对Mg-Y合金中高温力学行为的较为完整的阐述。分析发现,Mg-Y合金的抗蠕变性能随着Y含量的升高而明显提升,蠕变各向异性则有所减弱;对Mg-Y合金抗蠕变性能进行提升,一是可对Y含量较低的合金进行预置孪晶,二是可对Y含量较高的合金施加时效处理。精细调控Mg-Y合金微观结构,长远来看仍是低成本高性能镁合金研究开发的重要途径。

With the increasing demands on lightweight structural materials in modern industries,magnesium(Mg)alloys with high specific strength and low density have attracted extensive attentions.Taking special elements as the main alloying elements can greatly improve the creep resistance and thermal stability of magnesium alloys.Especially,the yttrium(Y)element is not only cheaper,but also has higher solution strengthening effect and more excellent thermal stability after the formation of Mg-Y alloys,with great application potentials in the future.Starting from the thermal deformation behavior of Mg-Y alloys,the influence of Y element content on the creep behavior and creep resistance of Mg-Y alloys was combed,and the methods to improve the creep resistance of Mg-Y alloy were discussed,thus forming a relatively complete exposition of the mechanical behavior of Mg-Y alloys at medium-to-high temperatures.It was found that the creep resistance of Mg-Y alloys was obviously improved with the increase of Y content,while the creep anisotropy was weakened;to improve the creep resistance of Mg-Y alloys,on the one hand,the twin density of alloys with low Y content can be preset,and on the other hand,aging treatment can be exerted on the alloys with high Y content.In the long run,fine control of the micro structure of Mg-Y alloys will still be an important way to research and develop low-cost and highperformance magnesium alloys.